TOPCon Solar Cell Edge Passivation for Lower Recombination
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Solution Overview
Problem
The existing tunnel oxide passivated contact (TOPCon) solar cells experience significant carrier recombination at the edge surface, leading to reduced efficiency due to unaddressed recombination loss at the edge surface.
Innovation Solution
The solar cell design includes a substrate with a doped conducting layer and passivation layers, where an anti-reflection layer or a second passivation layer is strategically deposited on the side surfaces to provide passivation, reducing carrier recombination and enhancing efficiency by covering at least part of the side surfaces and edges, thereby protecting the edge surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passivation contact structure is prepared on the surface of the cell to reduce metal contact recombination current, then open circuit voltage and short circuit current are increased, but carrier recombination occurs at the edge surface resulting in low efficiency
Solution Approach 1:
The patent extends the passivation coverage from the traditional two-dimensional plane (front and back surfaces) to include the three-dimensional edge surfaces of the solar cell. By forming passivation layers on the side surfaces, the solution addresses carrier recombination in the previously neglected third dimension, thereby reducing energy loss while maintaining the voltage benefits of the passivation contact structure.
Solution Approach 2:
The patent applies different passivation structures to different locations of the solar cell. Specifically, it forms a first passivation layer on the front surface, a second passivation layer on the back surface, and crucially, edge surface passivation layers on the side surfaces. This localized approach ensures that each region receives the appropriate passivation treatment needed to minimize recombination at that specific location.
2Productivity
If edge surface passivation is implemented to reduce carrier recombination, then solar cell efficiency is increased, but device structure and manufacturing process are made more complex
Solution Approach 1:
The patent employs the same types of materials and deposition techniques for both the conventional surface passivation layers and the new edge surface passivation layers. The first passivation layer on the front surface, the second passivation layer on the back surface, and the edge surface passivation layers all use consistent material systems and formation methods. This universality allows the edge passivation to be integrated into the existing manufacturing workflow without requiring entirely new processes, thereby limiting the increase in device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces carrier recombination at the edge surface, leading to improved photoelectric conversion efficiency by ensuring comprehensive passivation of the edge surfaces and edges of the solar cell.
Implementation Method 1
The anti-reflection layer or second passivation layer is deposited on the side surfaces of the substrate during manufacturing
Data Source
AI summary
The application provides a solar cell, a manufacturing method, a photovoltaic device and a photovoltaic system. The solar cell includes a substrate, a doped conducting layer, a first passivation layer, an anti-reflection layer, a passivation contact layer, and a second passivation layer. The substrate includes opposite first and second surfaces, and side surfaces between the first and second surfaces. The doped conducting layer and the first passivation layer are sequentially stacked on the first surface. The anti-reflection layer is stacked on the first passivation layer and covers the first surface to cover the first passivation layer. The passivation contact layer is stacked on the second surface. The second passivation layer is stacked on the passivation contact layer and covers the second surface to cover the passivation contact layer. The anti-reflection layer or the second passivation layer covers at least part of at least one side surface of the substrate.